Dividers



(No Model.)

G. M. PRATT.

DIVIDBRS; v

No. 336,868. Patented Feb. 23, 1886.

UNITED STATES PATENT OFFICE.

GEORGE ir. PRATT, OE MIDDLETOWN, CONNECTICUT.

DIVIDERS.

SJPBCIFICATION forming part of'Letters Patent No. 336,868, dated February 23, 1886.

Application filed November 9, 1885. Serial No. 182,264. (No model.)

To all whom it may concern:

Be it known that I, GEORGE lll. PRATT. a citizen of the United States, residing at Middletown, in the county of Middlesex and State of Connecticut, have invented new and useful Improvements in Dividers, of which the following is a specification.

y invention relates to and consists in certain novel improvements in dividers, the purpose thereof being to simplify and improve the construction of this class of instruments and to provide the same with a micrometer-adjustment of increased accuracy.

It is also the purposel of my invention to provide a pair of dividers having a double means of adjustment for the adjustable leg, whereof one adjustment is by a graduated micrometer-screw.

Referring to the accompanying drawings, Figure 1 is a side elevation of a device embodying my invention. Fig. 2 is a similar view partly in section. Fig. 3 is an end elevation.

In the said drawings,the reference-numeral 1 designates the .pivotal arm of a pair of dividers constructed in accordance with my invention. This arm has a center point, 2, and a milled staff, 3, and mounted thereon between the two is a bracket, 3, cast or otherwise formed upon said arm, and having a thumb-nut, 4, journaled therein in any suitable manner. Meshing with said nut and supported in the two branches of the bracket 3 is an exteriorly-threaded sleeve, 5, having a longitudinal slot, 6, which engages with a nger, 7, detachably connected with the bracket 3 by a screw, 7. This nger prevents the sleeve from rotating as the screwnut is turned in its bearings, as it engages with the slot 6 in the threaded sleeve. Passing through said sleeve is al bar, 8, carrying an arm, 9, which may be and preferably is integral with the said arm, and which serves as the sweep-arm of the dividers. The bar 8 has movement in the sleeve 5, to give adjustnient to its point relatively to the pivot-point 2, and it may be held at any desired point in the following manner.

In the centering or pivotal arm 1 is formed a cavity, which receives a bar, 10, having its end entering the slot 6 in the sleeve-5' and ythe sweep-arm, may be adjusted in either direction.

In order to gage the adjustment of the sweep-auml propose to flatten the upper portion of the bar 8, as shown at 8, and to inscribe thereon the graduations of inch and fractional inch marks. I also provide the thumb-nut 4 with a beveled portion, 4, and graduate the latter in such manner that the operator may by a partial revolution give an extremely delicate but uniform adjustment to the sweep-arm 9.

It will readily be seen that by means ofthe setscrew 13 both the sweep-arm and the thumb-nut may be locked against movement.

Having thus described my invention, what I claim is- 1. The combination of the pivotal arm having the center point, 2, an externallyscrew-threaded sleeve arranged transversely through the arm, a rotating nut engaging said sleeve to adjust it longitudinally, and asweep-arm movable with the sleeve in its adjustment, and also capable of longitudinal adjustment in the sleeve independent of any movement of the latter, substantially as described.

2. In a pair of dividers, a sweep-arm, a pivotal statil carrying a bracket having a sleeve supporting said arm, a thumb nut meshing with said sleeve, and a binding-rod engaging with the adjustable arm and actuated by a nut on the staff, substantially as described.

3. In a pair of dividers, a pivotal staff containing a binding-rod and having a set-Screw with interposed spring between it and said rod, a bracket formed or mounted on said staff, a thumb-nut journaled in said bracket, a sleeve having an exterior' thread engaging ICO with said nut, and an adjustable sweeparm having bearing in said sleeve and engaging with said binding-rod through a slot in the 1 sleeve, substantially as described.

4. In a pair of dividers, the combination, with the staffarm having a bracket, of a thumb-nut journaled in said bracket, a sweeparm having bearing in a sleeve meshing with a thunib-nnt,and a binding-rod actuated by a 1o set-screw in the staff and engaging with the GEO. M. PRATT.

fitnessesz HENRY WOODWARD, GEO. LEONARD. 

